Support an option to only set the AWS_PROFILE variable

[felipe1982]

Sometimes it's useful to have AWS_ACCESS_KEY and other associated env vars, but other times it is better to just use AWS_PROFILE, and unset all the other AWS_* variables.

When I refresh my creds, I normally have to re-run awsume . If only AWS_PROFILE was set, I would not need to do that.

Workflow example

1. set credentials using saml (saml2aws)
2. run awsume
3. aws s3 ls
4. credentials time out
5. set credentials using saml
6. run awsume # I could save this step #
7. aws s3 ls

[1oglop1]

I use awsume together with (direnv)[https://direnv.net/]
you can pack all these steps in one script inside .envrc or have direnv watch .aws/credentials for change - it should change by saml2aws.
Then you can just: cd <my_project>, sign in, work. And when credetials expire direnv reload.

Honestly, most tools I worked with did not honour AWS_PROFILE - this is where I find direnv best tool to organize it.

I did not use saml2aws but it seems to have an option (script)[https://github.com/Versent/saml2aws#saml2aws-script] - but I assume it may not work for your use case because you have to authenticate against the parent account and then assume the role in the child account.